Abstract: Error analysis of parallel seam welding platform is of great significance for packaging quality in micro-crystal resonator. Aiming at the accuracy requirement of the platform, its error sources are analyzed and the main line of error transmission is determined. Based on the error transferring rules and the platform's structure, the homogeneous coordinate transformation method is improved by establishing three characteristic coordinate systems, and the influence of machining error and assembly error on the platform's position error is analyzed. The assembly error models of the X-Y plane and Z-axis direction in the seam welding platform are set up, and the general position error model of the platform is given by integrating the above two basic models. The general error model obtained is simulated and analyzed by MATLAB, which verifies the model correctness and obtains the allowable error variation range with satisfying the important dimensional accuracy requirements.